In plants for the filling of containers with a liquid bulk product, e.g. in container filling installations, with certain filling methods, a vacuum or negative pressure is needed and used to remove ambient air, and, in connection with this, the oxygen contained in the ambient air, from the containers to be filled. This step is typically carried out in a one-stage or multi-stage pre-processing phase preceding the actual filling phase.
In known vacuum devices that are used in the drinks industry, it is known to form a vacuum device by a single vacuum pump. This vacuum pump is adapted, in terms of its vacuum power and its electrical power, to the vacuum or suction power needed for the particular installation in both normal operation and in maximum operation. Changes or fluctuations in the currently necessary vacuum or suction power can then be taken into account solely within certain limits by changing the speed of the vacuum pump.
This approach results in the manufacturers of such installations providing different vacuum pumps adapted to the vacuum power required in each case for different vacuum devices with differing vacuum power levels.
Among the disadvantages of this arrangement are an increased outlay for maintaining supplies and stocks of different vacuum pumps and their spare parts, associated increased costs, and an inability to change the vacuum and suction power of the relevant vacuum device by more than a limited extent.